the policy of maintaining control over one's subordinates or subjects by encouraging dissent between them, thereby preventing them from uniting to overthrow one
分而治之
the politics of divide and rule in society.
对社会实行分而治之的政治。
(of a group which should be coherent) split by factional interests
（本该一致的团体因不同派系利益而）分裂的
the regime is profoundly divided against itself.
该政权四分五裂。